216 V. S. NATIONAL MUSEUM BULLETIN 217 



Family CINCLIDAE: Dippers 

 Cinclus mexicanus unicolor Bonaparte 



We did not see in the ice-covered arctic rivers any of those infre- 

 quent areas where the water remained open and where dippers remain 

 in winter, usually in pairs, Stephen Frost carefully described two 

 dippers he had seen in April in the stretch of open water near the 

 mouth of Bluefish Creek and said that in February 1956 he saw similar 

 small birds at several of the open water stretches over 200 miles from 

 the mouth of the extraordinarily crooked Black Eiver. Joe Kay con- 

 firmed these observations from his own much earlier observations and 

 named the dipper as soon as he saw its picture. 



The Indian name for this bird is Tzi rsui. 



Family TURDIDAE: Thrushes, Solitaires, Bluebirds 

 Turdus migratorius migratorius Linnaeus 



Males Females 





Weight 



Fat 



Testes (mm.) 



Date 



{Q.) 







May 15 



71.6 



LF 



5x11, 8x12.5 





86.7 



LF 



6x14, 6x15 





74.3 



LF 



7x12, 6.5x11 



May 16 



81.0 



LF 



7x11, 8x10 





76.2 



LF 



7x11, 7x10 



June 6 



80.0 



F 



9x14, 10x13 



June 9 



60.2 



LF 



8x13, 9x15 





69.1 





9x18, 10x15 



(aver.) 



73.6 







June 2 









WeigfU Fat Eggs 



75. 2 LF 2 mm. 



79.4 LF 1 mm. 



4 fresh eggs, 4 

 slightly incu- 

 bated eggs 



The first robin was seen on May 8. It was shy and quiet and a week 

 elapsed before more than one was noticed, although a few may have 

 been about but not observed. On May 15 a few more robins were 

 about and their numbers, noise and swift and often aggressive flights 

 rapidly became conspicuous until on May 18 the village appeared to 

 contain more than a suitable population for nesting. The robins 

 seemed to be of this opinion also for their quarreling continued until 

 the latter part of May. "We then thought that some robins must have 

 left the area, for, in addition to the subsidence of their activity, their 

 numbers appeared to decrease. 



Two nests were found on June 2. These we presume to have been 

 laid about May 25 and 27, 10 days after the conspicuous influx of 

 robins on May 15, but 17 days after the first was seen. In 1952 the 

 first robin was noted at Anaktuvuk on May 18 and the first egg was 

 reported on June 3, an interval of 16 days. 



The maximum testes size was observed in a robin collected on June 

 9. Judging from the first eggs, some males were in breeding condi- 

 tion by May 25. 



